diff mbox series

[1/5] xfs: store inode btree block counts in AGI header

Message ID 159901535858.547164.11928856896363415325.stgit@magnolia
State Accepted
Headers show
Series xfs: add inode btree blocks counters to the AGI header | expand

Commit Message

Darrick J. Wong Sept. 2, 2020, 2:55 a.m. UTC
From: Darrick J. Wong <darrick.wong@oracle.com>

Add a btree block usage counters for both inode btrees to the AGI header
so that we don't have to walk the entire finobt at mount time to create
the per-AG reservations.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/libxfs/xfs_ag.c           |    5 +++++
 fs/xfs/libxfs/xfs_format.h       |   18 +++++++++++++++++-
 fs/xfs/libxfs/xfs_ialloc.c       |    1 +
 fs/xfs/libxfs/xfs_ialloc_btree.c |   24 ++++++++++++++++++++++++
 fs/xfs/xfs_ondisk.h              |    2 +-
 fs/xfs/xfs_super.c               |    4 ++++
 6 files changed, 52 insertions(+), 2 deletions(-)

Comments

Brian Foster Sept. 2, 2020, 1:23 p.m. UTC | #1
On Tue, Sep 01, 2020 at 07:55:58PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Add a btree block usage counters for both inode btrees to the AGI header
> so that we don't have to walk the entire finobt at mount time to create
> the per-AG reservations.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---

A couple nits..

>  fs/xfs/libxfs/xfs_ag.c           |    5 +++++
>  fs/xfs/libxfs/xfs_format.h       |   18 +++++++++++++++++-
>  fs/xfs/libxfs/xfs_ialloc.c       |    1 +
>  fs/xfs/libxfs/xfs_ialloc_btree.c |   24 ++++++++++++++++++++++++
>  fs/xfs/xfs_ondisk.h              |    2 +-
>  fs/xfs/xfs_super.c               |    4 ++++
>  6 files changed, 52 insertions(+), 2 deletions(-)
> 
> 
> diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c
> index 8cf73fe4338e..9331f3516afa 100644
> --- a/fs/xfs/libxfs/xfs_ag.c
> +++ b/fs/xfs/libxfs/xfs_ag.c
> @@ -333,6 +333,11 @@ xfs_agiblock_init(
>  	}
>  	for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++)
>  		agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
> +	if (xfs_sb_version_hasinobtcounts(&mp->m_sb)) {
> +		agi->agi_iblocks = cpu_to_be32(1);
> +		if (xfs_sb_version_hasfinobt(&mp->m_sb))
> +			agi->agi_fblocks = cpu_to_be32(1);
> +	}
>  }
>  
>  typedef void (*aghdr_init_work_f)(struct xfs_mount *mp, struct xfs_buf *bp,
> diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
> index 31b7ece985bb..03cbedb7eafc 100644
> --- a/fs/xfs/libxfs/xfs_format.h
> +++ b/fs/xfs/libxfs/xfs_format.h
> @@ -449,6 +449,7 @@ xfs_sb_has_compat_feature(
>  #define XFS_SB_FEAT_RO_COMPAT_FINOBT   (1 << 0)		/* free inode btree */
>  #define XFS_SB_FEAT_RO_COMPAT_RMAPBT   (1 << 1)		/* reverse map btree */
>  #define XFS_SB_FEAT_RO_COMPAT_REFLINK  (1 << 2)		/* reflinked files */
> +#define XFS_SB_FEAT_RO_COMPAT_INOBTCNT (1 << 3)		/* inobt block counts */
>  #define XFS_SB_FEAT_RO_COMPAT_ALL \
>  		(XFS_SB_FEAT_RO_COMPAT_FINOBT | \
>  		 XFS_SB_FEAT_RO_COMPAT_RMAPBT | \
> @@ -563,6 +564,17 @@ static inline bool xfs_sb_version_hasreflink(struct xfs_sb *sbp)
>  		(sbp->sb_features_ro_compat & XFS_SB_FEAT_RO_COMPAT_REFLINK);
>  }
>  
> +/*
> + * Inode btree block counter.  We record the number of inobt and finobt blocks
> + * in the AGI header so that we can skip the finobt walk at mount time when
> + * setting up per-AG reservations.
> + */
> +static inline bool xfs_sb_version_hasinobtcounts(struct xfs_sb *sbp)
> +{
> +	return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5 &&
> +		(sbp->sb_features_ro_compat & XFS_SB_FEAT_RO_COMPAT_INOBTCNT);
> +}
> +
>  /*
>   * end of superblock version macros
>   */
> @@ -765,6 +777,9 @@ typedef struct xfs_agi {
>  	__be32		agi_free_root; /* root of the free inode btree */
>  	__be32		agi_free_level;/* levels in free inode btree */
>  
> +	__be32		agi_iblocks;	/* inobt blocks used */
> +	__be32		agi_fblocks;	/* finobt blocks used */
> +
>  	/* structure must be padded to 64 bit alignment */
>  } xfs_agi_t;
>  
> @@ -785,7 +800,8 @@ typedef struct xfs_agi {
>  #define	XFS_AGI_ALL_BITS_R1	((1 << XFS_AGI_NUM_BITS_R1) - 1)
>  #define	XFS_AGI_FREE_ROOT	(1 << 11)
>  #define	XFS_AGI_FREE_LEVEL	(1 << 12)
> -#define	XFS_AGI_NUM_BITS_R2	13
> +#define	XFS_AGI_IBLOCKS		(1 << 13) /* both inobt/finobt block counters */
> +#define	XFS_AGI_NUM_BITS_R2	14

I still find it a little odd that we'd log both fields if only one might
be supported/modified, as opposed to just tracking them both
independently with a couple extra lines of code. That said, I don't see
it as a functional problem that couldn't be fixed later.

>  
>  /* disk block (xfs_daddr_t) in the AG */
>  #define XFS_AGI_DADDR(mp)	((xfs_daddr_t)(2 << (mp)->m_sectbb_log))
> diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c
> index f742a96a2fe1..fef1d94c60a4 100644
> --- a/fs/xfs/libxfs/xfs_ialloc.c
> +++ b/fs/xfs/libxfs/xfs_ialloc.c
> @@ -2473,6 +2473,7 @@ xfs_ialloc_log_agi(
>  		offsetof(xfs_agi_t, agi_unlinked),
>  		offsetof(xfs_agi_t, agi_free_root),
>  		offsetof(xfs_agi_t, agi_free_level),
> +		offsetof(xfs_agi_t, agi_iblocks),
>  		sizeof(xfs_agi_t)
>  	};
>  #ifdef DEBUG
> diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c
> index 3c8aebc36e64..cf51b342b6ef 100644
> --- a/fs/xfs/libxfs/xfs_ialloc_btree.c
> +++ b/fs/xfs/libxfs/xfs_ialloc_btree.c
> @@ -67,6 +67,28 @@ xfs_finobt_set_root(
>  			   XFS_AGI_FREE_ROOT | XFS_AGI_FREE_LEVEL);
>  }
>  
> +/* Update the inode btree block counter for this btree. */
> +static inline void
> +xfs_inobt_mod_blockcount(
> +	struct xfs_btree_cur	*cur,
> +	int			howmuch)
> +{
> +	struct xfs_buf		*agbp = cur->bc_ag.agbp;
> +	struct xfs_agi		*agi = agbp->b_addr;
> +
> +	if (!xfs_sb_version_hasinobtcounts(&cur->bc_mp->m_sb))
> +		return;
> +
> +	if (cur->bc_btnum == XFS_BTNUM_FINO &&
> +	    xfs_sb_version_hasfinobt(&cur->bc_mp->m_sb)) {

This check might be spurious because I suspect you wouldn't get a finobt
cursor without the feature enabled. Those nits aside:

Reviewed-by: Brian Foster <bfoster@redhat.com>

> +		be32_add_cpu(&agi->agi_fblocks, howmuch);
> +		xfs_ialloc_log_agi(cur->bc_tp, agbp, XFS_AGI_IBLOCKS);
> +	} else if (cur->bc_btnum == XFS_BTNUM_INO) {
> +		be32_add_cpu(&agi->agi_iblocks, howmuch);
> +		xfs_ialloc_log_agi(cur->bc_tp, agbp, XFS_AGI_IBLOCKS);
> +	}
> +}
> +
>  STATIC int
>  __xfs_inobt_alloc_block(
>  	struct xfs_btree_cur	*cur,
> @@ -102,6 +124,7 @@ __xfs_inobt_alloc_block(
>  
>  	new->s = cpu_to_be32(XFS_FSB_TO_AGBNO(args.mp, args.fsbno));
>  	*stat = 1;
> +	xfs_inobt_mod_blockcount(cur, 1);
>  	return 0;
>  }
>  
> @@ -134,6 +157,7 @@ __xfs_inobt_free_block(
>  	struct xfs_buf		*bp,
>  	enum xfs_ag_resv_type	resv)
>  {
> +	xfs_inobt_mod_blockcount(cur, -1);
>  	return xfs_free_extent(cur->bc_tp,
>  			XFS_DADDR_TO_FSB(cur->bc_mp, XFS_BUF_ADDR(bp)), 1,
>  			&XFS_RMAP_OINFO_INOBT, resv);
> diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
> index 5f04d8a5ab2a..acb9b737fe6b 100644
> --- a/fs/xfs/xfs_ondisk.h
> +++ b/fs/xfs/xfs_ondisk.h
> @@ -23,7 +23,7 @@ xfs_check_ondisk_structs(void)
>  	XFS_CHECK_STRUCT_SIZE(struct xfs_acl_entry,		12);
>  	XFS_CHECK_STRUCT_SIZE(struct xfs_agf,			224);
>  	XFS_CHECK_STRUCT_SIZE(struct xfs_agfl,			36);
> -	XFS_CHECK_STRUCT_SIZE(struct xfs_agi,			336);
> +	XFS_CHECK_STRUCT_SIZE(struct xfs_agi,			344);
>  	XFS_CHECK_STRUCT_SIZE(struct xfs_bmbt_key,		8);
>  	XFS_CHECK_STRUCT_SIZE(struct xfs_bmbt_rec,		16);
>  	XFS_CHECK_STRUCT_SIZE(struct xfs_bmdr_block,		4);
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 71ac6c1cdc36..c7ffcb57b586 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -1549,6 +1549,10 @@ xfs_fc_fill_super(
>  		goto out_filestream_unmount;
>  	}
>  
> +	if (xfs_sb_version_hasinobtcounts(&mp->m_sb))
> +		xfs_warn(mp,
> + "EXPERIMENTAL inode btree counters feature in use. Use at your own risk!");
> +
>  	error = xfs_mountfs(mp);
>  	if (error)
>  		goto out_filestream_unmount;
>
Darrick J. Wong Sept. 2, 2020, 5:13 p.m. UTC | #2
On Wed, Sep 02, 2020 at 09:23:36AM -0400, Brian Foster wrote:
> On Tue, Sep 01, 2020 at 07:55:58PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@oracle.com>
> > 
> > Add a btree block usage counters for both inode btrees to the AGI header
> > so that we don't have to walk the entire finobt at mount time to create
> > the per-AG reservations.
> > 
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > ---
> 
> A couple nits..
> 
> >  fs/xfs/libxfs/xfs_ag.c           |    5 +++++
> >  fs/xfs/libxfs/xfs_format.h       |   18 +++++++++++++++++-
> >  fs/xfs/libxfs/xfs_ialloc.c       |    1 +
> >  fs/xfs/libxfs/xfs_ialloc_btree.c |   24 ++++++++++++++++++++++++
> >  fs/xfs/xfs_ondisk.h              |    2 +-
> >  fs/xfs/xfs_super.c               |    4 ++++
> >  6 files changed, 52 insertions(+), 2 deletions(-)
> > 
> > 
> > diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c
> > index 8cf73fe4338e..9331f3516afa 100644
> > --- a/fs/xfs/libxfs/xfs_ag.c
> > +++ b/fs/xfs/libxfs/xfs_ag.c
> > @@ -333,6 +333,11 @@ xfs_agiblock_init(
> >  	}
> >  	for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++)
> >  		agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
> > +	if (xfs_sb_version_hasinobtcounts(&mp->m_sb)) {
> > +		agi->agi_iblocks = cpu_to_be32(1);
> > +		if (xfs_sb_version_hasfinobt(&mp->m_sb))
> > +			agi->agi_fblocks = cpu_to_be32(1);
> > +	}
> >  }
> >  
> >  typedef void (*aghdr_init_work_f)(struct xfs_mount *mp, struct xfs_buf *bp,
> > diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
> > index 31b7ece985bb..03cbedb7eafc 100644
> > --- a/fs/xfs/libxfs/xfs_format.h
> > +++ b/fs/xfs/libxfs/xfs_format.h
> > @@ -449,6 +449,7 @@ xfs_sb_has_compat_feature(
> >  #define XFS_SB_FEAT_RO_COMPAT_FINOBT   (1 << 0)		/* free inode btree */
> >  #define XFS_SB_FEAT_RO_COMPAT_RMAPBT   (1 << 1)		/* reverse map btree */
> >  #define XFS_SB_FEAT_RO_COMPAT_REFLINK  (1 << 2)		/* reflinked files */
> > +#define XFS_SB_FEAT_RO_COMPAT_INOBTCNT (1 << 3)		/* inobt block counts */
> >  #define XFS_SB_FEAT_RO_COMPAT_ALL \
> >  		(XFS_SB_FEAT_RO_COMPAT_FINOBT | \
> >  		 XFS_SB_FEAT_RO_COMPAT_RMAPBT | \
> > @@ -563,6 +564,17 @@ static inline bool xfs_sb_version_hasreflink(struct xfs_sb *sbp)
> >  		(sbp->sb_features_ro_compat & XFS_SB_FEAT_RO_COMPAT_REFLINK);
> >  }
> >  
> > +/*
> > + * Inode btree block counter.  We record the number of inobt and finobt blocks
> > + * in the AGI header so that we can skip the finobt walk at mount time when
> > + * setting up per-AG reservations.
> > + */
> > +static inline bool xfs_sb_version_hasinobtcounts(struct xfs_sb *sbp)
> > +{
> > +	return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5 &&
> > +		(sbp->sb_features_ro_compat & XFS_SB_FEAT_RO_COMPAT_INOBTCNT);
> > +}
> > +
> >  /*
> >   * end of superblock version macros
> >   */
> > @@ -765,6 +777,9 @@ typedef struct xfs_agi {
> >  	__be32		agi_free_root; /* root of the free inode btree */
> >  	__be32		agi_free_level;/* levels in free inode btree */
> >  
> > +	__be32		agi_iblocks;	/* inobt blocks used */
> > +	__be32		agi_fblocks;	/* finobt blocks used */
> > +
> >  	/* structure must be padded to 64 bit alignment */
> >  } xfs_agi_t;
> >  
> > @@ -785,7 +800,8 @@ typedef struct xfs_agi {
> >  #define	XFS_AGI_ALL_BITS_R1	((1 << XFS_AGI_NUM_BITS_R1) - 1)
> >  #define	XFS_AGI_FREE_ROOT	(1 << 11)
> >  #define	XFS_AGI_FREE_LEVEL	(1 << 12)
> > -#define	XFS_AGI_NUM_BITS_R2	13
> > +#define	XFS_AGI_IBLOCKS		(1 << 13) /* both inobt/finobt block counters */
> > +#define	XFS_AGI_NUM_BITS_R2	14
> 
> I still find it a little odd that we'd log both fields if only one might
> be supported/modified, as opposed to just tracking them both
> independently with a couple extra lines of code. That said, I don't see
> it as a functional problem that couldn't be fixed later.

Yeah.  I didn't want to go burning two bits for this since in all
likelihood the finobt will be enabled anytime inobtcounts are active.

I guess we could revisit that if someone uses db to frankenstein a
filesystem into having inobtcounts without a finobt and shows that the
overhead makes a difference, but the xfs_admin and mkfs tools aren't
going to allow that combination.

> >  
> >  /* disk block (xfs_daddr_t) in the AG */
> >  #define XFS_AGI_DADDR(mp)	((xfs_daddr_t)(2 << (mp)->m_sectbb_log))
> > diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c
> > index f742a96a2fe1..fef1d94c60a4 100644
> > --- a/fs/xfs/libxfs/xfs_ialloc.c
> > +++ b/fs/xfs/libxfs/xfs_ialloc.c
> > @@ -2473,6 +2473,7 @@ xfs_ialloc_log_agi(
> >  		offsetof(xfs_agi_t, agi_unlinked),
> >  		offsetof(xfs_agi_t, agi_free_root),
> >  		offsetof(xfs_agi_t, agi_free_level),
> > +		offsetof(xfs_agi_t, agi_iblocks),
> >  		sizeof(xfs_agi_t)
> >  	};
> >  #ifdef DEBUG
> > diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c
> > index 3c8aebc36e64..cf51b342b6ef 100644
> > --- a/fs/xfs/libxfs/xfs_ialloc_btree.c
> > +++ b/fs/xfs/libxfs/xfs_ialloc_btree.c
> > @@ -67,6 +67,28 @@ xfs_finobt_set_root(
> >  			   XFS_AGI_FREE_ROOT | XFS_AGI_FREE_LEVEL);
> >  }
> >  
> > +/* Update the inode btree block counter for this btree. */
> > +static inline void
> > +xfs_inobt_mod_blockcount(
> > +	struct xfs_btree_cur	*cur,
> > +	int			howmuch)
> > +{
> > +	struct xfs_buf		*agbp = cur->bc_ag.agbp;
> > +	struct xfs_agi		*agi = agbp->b_addr;
> > +
> > +	if (!xfs_sb_version_hasinobtcounts(&cur->bc_mp->m_sb))
> > +		return;
> > +
> > +	if (cur->bc_btnum == XFS_BTNUM_FINO &&
> > +	    xfs_sb_version_hasfinobt(&cur->bc_mp->m_sb)) {
> 
> This check might be spurious because I suspect you wouldn't get a finobt
> cursor without the feature enabled. Those nits aside:

Heh, yeah.  I'll fix that one up, at least.  Thanks for the review!

--D

> Reviewed-by: Brian Foster <bfoster@redhat.com>
> 
> > +		be32_add_cpu(&agi->agi_fblocks, howmuch);
> > +		xfs_ialloc_log_agi(cur->bc_tp, agbp, XFS_AGI_IBLOCKS);
> > +	} else if (cur->bc_btnum == XFS_BTNUM_INO) {
> > +		be32_add_cpu(&agi->agi_iblocks, howmuch);
> > +		xfs_ialloc_log_agi(cur->bc_tp, agbp, XFS_AGI_IBLOCKS);
> > +	}
> > +}
> > +
> >  STATIC int
> >  __xfs_inobt_alloc_block(
> >  	struct xfs_btree_cur	*cur,
> > @@ -102,6 +124,7 @@ __xfs_inobt_alloc_block(
> >  
> >  	new->s = cpu_to_be32(XFS_FSB_TO_AGBNO(args.mp, args.fsbno));
> >  	*stat = 1;
> > +	xfs_inobt_mod_blockcount(cur, 1);
> >  	return 0;
> >  }
> >  
> > @@ -134,6 +157,7 @@ __xfs_inobt_free_block(
> >  	struct xfs_buf		*bp,
> >  	enum xfs_ag_resv_type	resv)
> >  {
> > +	xfs_inobt_mod_blockcount(cur, -1);
> >  	return xfs_free_extent(cur->bc_tp,
> >  			XFS_DADDR_TO_FSB(cur->bc_mp, XFS_BUF_ADDR(bp)), 1,
> >  			&XFS_RMAP_OINFO_INOBT, resv);
> > diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
> > index 5f04d8a5ab2a..acb9b737fe6b 100644
> > --- a/fs/xfs/xfs_ondisk.h
> > +++ b/fs/xfs/xfs_ondisk.h
> > @@ -23,7 +23,7 @@ xfs_check_ondisk_structs(void)
> >  	XFS_CHECK_STRUCT_SIZE(struct xfs_acl_entry,		12);
> >  	XFS_CHECK_STRUCT_SIZE(struct xfs_agf,			224);
> >  	XFS_CHECK_STRUCT_SIZE(struct xfs_agfl,			36);
> > -	XFS_CHECK_STRUCT_SIZE(struct xfs_agi,			336);
> > +	XFS_CHECK_STRUCT_SIZE(struct xfs_agi,			344);
> >  	XFS_CHECK_STRUCT_SIZE(struct xfs_bmbt_key,		8);
> >  	XFS_CHECK_STRUCT_SIZE(struct xfs_bmbt_rec,		16);
> >  	XFS_CHECK_STRUCT_SIZE(struct xfs_bmdr_block,		4);
> > diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> > index 71ac6c1cdc36..c7ffcb57b586 100644
> > --- a/fs/xfs/xfs_super.c
> > +++ b/fs/xfs/xfs_super.c
> > @@ -1549,6 +1549,10 @@ xfs_fc_fill_super(
> >  		goto out_filestream_unmount;
> >  	}
> >  
> > +	if (xfs_sb_version_hasinobtcounts(&mp->m_sb))
> > +		xfs_warn(mp,
> > + "EXPERIMENTAL inode btree counters feature in use. Use at your own risk!");
> > +
> >  	error = xfs_mountfs(mp);
> >  	if (error)
> >  		goto out_filestream_unmount;
> > 
>
diff mbox series

Patch

diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c
index 8cf73fe4338e..9331f3516afa 100644
--- a/fs/xfs/libxfs/xfs_ag.c
+++ b/fs/xfs/libxfs/xfs_ag.c
@@ -333,6 +333,11 @@  xfs_agiblock_init(
 	}
 	for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++)
 		agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
+	if (xfs_sb_version_hasinobtcounts(&mp->m_sb)) {
+		agi->agi_iblocks = cpu_to_be32(1);
+		if (xfs_sb_version_hasfinobt(&mp->m_sb))
+			agi->agi_fblocks = cpu_to_be32(1);
+	}
 }
 
 typedef void (*aghdr_init_work_f)(struct xfs_mount *mp, struct xfs_buf *bp,
diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index 31b7ece985bb..03cbedb7eafc 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -449,6 +449,7 @@  xfs_sb_has_compat_feature(
 #define XFS_SB_FEAT_RO_COMPAT_FINOBT   (1 << 0)		/* free inode btree */
 #define XFS_SB_FEAT_RO_COMPAT_RMAPBT   (1 << 1)		/* reverse map btree */
 #define XFS_SB_FEAT_RO_COMPAT_REFLINK  (1 << 2)		/* reflinked files */
+#define XFS_SB_FEAT_RO_COMPAT_INOBTCNT (1 << 3)		/* inobt block counts */
 #define XFS_SB_FEAT_RO_COMPAT_ALL \
 		(XFS_SB_FEAT_RO_COMPAT_FINOBT | \
 		 XFS_SB_FEAT_RO_COMPAT_RMAPBT | \
@@ -563,6 +564,17 @@  static inline bool xfs_sb_version_hasreflink(struct xfs_sb *sbp)
 		(sbp->sb_features_ro_compat & XFS_SB_FEAT_RO_COMPAT_REFLINK);
 }
 
+/*
+ * Inode btree block counter.  We record the number of inobt and finobt blocks
+ * in the AGI header so that we can skip the finobt walk at mount time when
+ * setting up per-AG reservations.
+ */
+static inline bool xfs_sb_version_hasinobtcounts(struct xfs_sb *sbp)
+{
+	return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5 &&
+		(sbp->sb_features_ro_compat & XFS_SB_FEAT_RO_COMPAT_INOBTCNT);
+}
+
 /*
  * end of superblock version macros
  */
@@ -765,6 +777,9 @@  typedef struct xfs_agi {
 	__be32		agi_free_root; /* root of the free inode btree */
 	__be32		agi_free_level;/* levels in free inode btree */
 
+	__be32		agi_iblocks;	/* inobt blocks used */
+	__be32		agi_fblocks;	/* finobt blocks used */
+
 	/* structure must be padded to 64 bit alignment */
 } xfs_agi_t;
 
@@ -785,7 +800,8 @@  typedef struct xfs_agi {
 #define	XFS_AGI_ALL_BITS_R1	((1 << XFS_AGI_NUM_BITS_R1) - 1)
 #define	XFS_AGI_FREE_ROOT	(1 << 11)
 #define	XFS_AGI_FREE_LEVEL	(1 << 12)
-#define	XFS_AGI_NUM_BITS_R2	13
+#define	XFS_AGI_IBLOCKS		(1 << 13) /* both inobt/finobt block counters */
+#define	XFS_AGI_NUM_BITS_R2	14
 
 /* disk block (xfs_daddr_t) in the AG */
 #define XFS_AGI_DADDR(mp)	((xfs_daddr_t)(2 << (mp)->m_sectbb_log))
diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c
index f742a96a2fe1..fef1d94c60a4 100644
--- a/fs/xfs/libxfs/xfs_ialloc.c
+++ b/fs/xfs/libxfs/xfs_ialloc.c
@@ -2473,6 +2473,7 @@  xfs_ialloc_log_agi(
 		offsetof(xfs_agi_t, agi_unlinked),
 		offsetof(xfs_agi_t, agi_free_root),
 		offsetof(xfs_agi_t, agi_free_level),
+		offsetof(xfs_agi_t, agi_iblocks),
 		sizeof(xfs_agi_t)
 	};
 #ifdef DEBUG
diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c
index 3c8aebc36e64..cf51b342b6ef 100644
--- a/fs/xfs/libxfs/xfs_ialloc_btree.c
+++ b/fs/xfs/libxfs/xfs_ialloc_btree.c
@@ -67,6 +67,28 @@  xfs_finobt_set_root(
 			   XFS_AGI_FREE_ROOT | XFS_AGI_FREE_LEVEL);
 }
 
+/* Update the inode btree block counter for this btree. */
+static inline void
+xfs_inobt_mod_blockcount(
+	struct xfs_btree_cur	*cur,
+	int			howmuch)
+{
+	struct xfs_buf		*agbp = cur->bc_ag.agbp;
+	struct xfs_agi		*agi = agbp->b_addr;
+
+	if (!xfs_sb_version_hasinobtcounts(&cur->bc_mp->m_sb))
+		return;
+
+	if (cur->bc_btnum == XFS_BTNUM_FINO &&
+	    xfs_sb_version_hasfinobt(&cur->bc_mp->m_sb)) {
+		be32_add_cpu(&agi->agi_fblocks, howmuch);
+		xfs_ialloc_log_agi(cur->bc_tp, agbp, XFS_AGI_IBLOCKS);
+	} else if (cur->bc_btnum == XFS_BTNUM_INO) {
+		be32_add_cpu(&agi->agi_iblocks, howmuch);
+		xfs_ialloc_log_agi(cur->bc_tp, agbp, XFS_AGI_IBLOCKS);
+	}
+}
+
 STATIC int
 __xfs_inobt_alloc_block(
 	struct xfs_btree_cur	*cur,
@@ -102,6 +124,7 @@  __xfs_inobt_alloc_block(
 
 	new->s = cpu_to_be32(XFS_FSB_TO_AGBNO(args.mp, args.fsbno));
 	*stat = 1;
+	xfs_inobt_mod_blockcount(cur, 1);
 	return 0;
 }
 
@@ -134,6 +157,7 @@  __xfs_inobt_free_block(
 	struct xfs_buf		*bp,
 	enum xfs_ag_resv_type	resv)
 {
+	xfs_inobt_mod_blockcount(cur, -1);
 	return xfs_free_extent(cur->bc_tp,
 			XFS_DADDR_TO_FSB(cur->bc_mp, XFS_BUF_ADDR(bp)), 1,
 			&XFS_RMAP_OINFO_INOBT, resv);
diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
index 5f04d8a5ab2a..acb9b737fe6b 100644
--- a/fs/xfs/xfs_ondisk.h
+++ b/fs/xfs/xfs_ondisk.h
@@ -23,7 +23,7 @@  xfs_check_ondisk_structs(void)
 	XFS_CHECK_STRUCT_SIZE(struct xfs_acl_entry,		12);
 	XFS_CHECK_STRUCT_SIZE(struct xfs_agf,			224);
 	XFS_CHECK_STRUCT_SIZE(struct xfs_agfl,			36);
-	XFS_CHECK_STRUCT_SIZE(struct xfs_agi,			336);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_agi,			344);
 	XFS_CHECK_STRUCT_SIZE(struct xfs_bmbt_key,		8);
 	XFS_CHECK_STRUCT_SIZE(struct xfs_bmbt_rec,		16);
 	XFS_CHECK_STRUCT_SIZE(struct xfs_bmdr_block,		4);
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 71ac6c1cdc36..c7ffcb57b586 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1549,6 +1549,10 @@  xfs_fc_fill_super(
 		goto out_filestream_unmount;
 	}
 
+	if (xfs_sb_version_hasinobtcounts(&mp->m_sb))
+		xfs_warn(mp,
+ "EXPERIMENTAL inode btree counters feature in use. Use at your own risk!");
+
 	error = xfs_mountfs(mp);
 	if (error)
 		goto out_filestream_unmount;